The .450 Marlin is a fine cartridge. It was developed to safely duplicate the ballistics of "hot" handloads in the .45/70, which has been available in Marlin lever-action rifles for many years. A Marlin lever action in .450 would work--if you can tolerate the somewhat tough recoil. A big, hard-hitting bullet doesn't do any good if the bullet only hits air! If you're at all recoil sensitive, I'd suggest the good old .45/70 instead, in the Marlin 1895 Guide Gun with a handy 18-1/2-inch barrel. Loaded with Winchester's fine ammunition featuring the 300-grain Nosler Partition Gold, it will stop any varmint in North America at the close ranges you'd be shooting.